Radiological impact of cement, concrete and admixtures in Spain

It has been analyzed samples of portland cement (PC) with and without admixtures, samples of calcium aluminate cement (CAC) with different content of Al2O3 and specimens of concrete made with PC and CAC using High Resolution Gamma Spectrometry. The activity concentration index (I) is much less than 0.5 mSv y-1 for all the concrete specimens according to the Radiation protection document 112 of the European Commission. The PC without admixtures (CEM I 52,5 R) and the PC with addition of limestone (CEM II/BL 32,5 N) also have an I value much lower than 0.5 and the PC with the addition of fly ash and blast furnace slag (CEM IV/B (V) 32,5 N and III/A 42.5 N/SR) have an I value close to 0.6. The I value of the CAC used in the manufacture of structural precast concrete is of the order of 1 mSv y-1. Some of the CAC used in refractory concrete reaches a value close to 2 mSv y-1.

Analysis of halogenated compounds in landfill gas

The authors thank the research project CTQ2008-05520 from the Spanish Ministry of Education and Science and PROMETEO/2009/043/FEDER from the Valencian Community Government (Spain) for the support provided.

Electrochemical behaviour of different redox probes on single wall carbon nanotube buckypaper-modified electrodes

In the present work, the electrochemical properties of single-walled carbon nanotube buckypapers (BPs) were examined in terms of carbon nanotubes nature and preparation conditions. The performance of the different free-standing single wall carbon nanotube sheets was evaluated via cyclic voltammetry of several redox probes in aqueous electrolyte. Significant differences are observed in the electron transfer kinetics of the buckypaper-modified electrodes for both the outer- and inner-sphere redox systems. These differences can be ascribed to the nature of the carbon nanotubes (nanotube diameter, chirality and aspect ratio), surface oxidation degree and type of functionalities. In the case of dopamine, ferrocene/ferrocenium, and quinone/hydroquinone redox systems the voltammetric response should be thought as a complex contribution of different tips and sidewall domains which act as mediators for the electron transfer between the adsorbate species and the molecules in solution. In the other redox systems only nanotube ends are active sites for the electron transfer. It is also interesting to point out that a higher electroactive surface area not always lead to an improvement in the electron transfer rate of various redox systems. In addition, the current densities produced by the redox reactions studied here are high enough to ensure a proper electrochemical signal, which enables the use of BPs in sensing devices.

En estil de fictes paraules que tenen sentits no fictes: anàlisi de locucions i col·locacions en Joan Roís de Corella en el context del llenguatge literari de la Corona d’Aragó en el segle XV

Aquest article presenta una mostra dels resultats de l’anàlisi detallada de locucions, col·locacions i altres elements fraseològics i d’ordre de mots significatius quant a la caracterització del cabal de llenguatge literari de Joan Roís de Corella. Aquesta anàlisi es fa amb metodologia interdisciplinar de base de lingüistica de corpus i de diacronia lingüistica, i amb el concurs de les tecnologies de la informació i la comunicació (humanitats digitals), que s’apliquen a l’anàlisi de l’aportació lèxica i estilística d’un autor clau com és Roís de Corella a fide calibrar el grau de sintonia i, alhora, d’especificitat del seu llenguatge literari; en quin grau coincideix el seu llenguatge literari amb el d’altres grans clàssics culturals de la Corona d’Aragó, i en què basa, alhora, Roís de Corella la clau de la seua mestria estilística.